1. Field of the Invention
The present invention relates to a display device, and more particularly, to a liquid crystal display device and a method of fabricating the same.
2. Description of the Related Art
The liquid crystal display (LCD) device has been most favored recently as an efficient and value-added next generation display device, due to its low power consumption and its portability. In general, the LCD includes a lower substrate and an upper substrate arranged facing the lower substrate with a liquid crystal layer interposed between the lower substrate and the upper substrate. The lower substrate has a thin film transistor and a pixel electrode formed thereon. The upper substrate has a black matrix layer, a color filter layer and a common electrode formed thereon. The lower and upper substrates maintain a constant cell gap using a spacer. In such an LCD, an electric field is formed between the lower and upper substrates by a pixel electrode and a common electrode to align liquid crystal molecules, and light transmittance is adjusted through the alignment of the liquid crystal molecules to thereby display images. The picture quality of an LCD device is influenced by the integrity of the liquid crystal layer interposed between the two substrates. For instance, if the liquid crystal material is over-filled or expands due to high temperature, gravity failure may occur.
FIG. 1 is a cross-sectional view of the related art LCD showing a gravity failure. As shown in FIG. 1, the related art LCD includes a lower substrate 10, an upper substrate 20, and a liquid crystal layer 40 interposed between the lower substrate 10 and the upper substrate 20. The lower substrate 10 has a thin film transistor (Tr) formed thereon. The upper substrate 20 has a color filter layer 21 and a black matrix layer 22 formed thereon. The lower substrate 10 and the upper substrate 20 are attached by a seal pattern 30. The lower and upper substrates 10 and 20 maintain a constant cell gap using pattern spacers 50. The liquid crystal layer 40 is formed by injecting a liquid crystal material into an inner space between the lower and upper substrates 10 and 20 defined by the pattern spacers 50.
A proper amount of the liquid crystal material should be injected into the inner space. However, it is difficult to control the injection amount of the liquid crystal material. Sometimes, the liquid crystal material may over-fill the inner space, which can result in a gravity failure. Over-filling can cause other problems. For example, when the temperature of the liquid crystal material is increased due to an external environment, the volume of the liquid crystal expands to become larger than the inner space. If such an expansion occurs, the pattern spacers 50 are detached from one of the two substrates such that a liquid crystal path ‘A’ may be generated. Through the liquid crystal path ‘A’, the liquid crystal is collected downward, so that the cell gap becomes non-uniform. The non-uniform cell gap deteriorates the quality of the LCD and may cause a touch failure. Gravity failure and the touch brightness failure become exacerbated as the screen size of the LCD increases.